Restless legs and iron deficiency: is iron really the cause?
The relief you are chasing is a night where your legs stay still long enough to fall asleep, and for a large share of women the lever that moves it is iron. Restless Legs Syndrome is, at its root, an iron-availability problem in the brain. The brain cells that keep your legs settled at night need iron to do their job, and when that supply runs thin the signal goes haywire after dark.
Here is the part that trips people up. You can be iron deficient in the brain while your blood iron looks perfectly fine. Researchers have repeatedly found low iron stores in the brains of adults with Restless Legs Syndrome even when their everyday blood results sit in the “normal” range.
So the absence of anaemia does not let iron off the hook. It just means the standard full blood count is the wrong tool for the question.
That is why so many women get told their iron is fine, leave the appointment, and still spend the night kicking the sheets off. The test that fits the problem is a different one, and most people have never been offered it by name.
What ferritin level do you need for restless legs?
When it comes to restless legs and ferritin, one number does most of the work. The marker you actually want to see is your serum ferritin, because ferritin reflects how much iron you have in storage rather than what is floating in your blood today.
The catch is that the ferritin level for restless legs that the research cares about sits much higher than the one used to diagnose anaemia. That single fact explains a lot of dismissed appointments.
The 2024 American Academy of Sleep Medicine guideline is clear on the cut-off. It suggests iron supplementation for adults with Restless Legs Syndrome whose serum ferritin sits at or below 75 micrograms per litre, or whose transferrin saturation drops under 20 per cent (AASM, 2024). When ferritin lands between 75 and 100, it points to intravenous iron rather than tablets.
Compare that to the standard lab, where ferritin can be flagged “normal” from around 15 or 30 upward, and you can see the gap. A result of 40 gets a tick from the system and is nowhere near enough to settle restless legs.
Here is the quick translation, so you can read your own result instead of waiting to be told what it means.
| Your ferritin result | What it means for restless legs | Sensible next step |
|---|---|---|
| Below 30 micrograms per litre | Genuinely low by any measure | Ask your GP about iron, oral or intravenous |
| 30 to 75 micrograms per litre | “Normal” on the lab sheet, low for restless legs | Worth raising; this is the most-missed band |
| 75 to 100 micrograms per litre | Borderline; tablets may not lift it enough | Ask whether intravenous iron is the better route |
| Above 100 micrograms per litre | Iron stores are unlikely to be your driver | Look at the other levers instead |
Ask for the ferritin and the transferrin saturation together, take the blood in the morning, and skip iron supplements and iron-rich food for 24 hours beforehand, because all three of those things change the reading.
What your body is lacking when you have Restless Legs (and what to do)
The question most women type into their phone at 1am is which deficiency is actually causing this, and it deserves an honest map rather than a supplement ad. The strongest single answer is iron, specifically iron stored and available in the brain, which shows up clinically as a low ferritin. If you only ever chase one thing on this list, chase that one.
After iron, the shortfalls that come up most often in the research are magnesium, vitamin D, vitamin B12, and folate. The evidence behind each is weaker than for iron and the effect on your legs is smaller, so treat them as second-tier.
If a blood test shows you are genuinely low on any of them, fixing it is worth doing for your overall health, and it might quieten your legs as a bonus. Magnesium in particular is a cheap, low-risk thing to trial, and the honest read on magnesium for Restless Legs walks through which form and dose are worth your fortnight.
What your body is almost certainly not short on, whatever the wellness internet sells you, is a proprietary “detox” blend, adrenal support, or a fistful of mystery electrolytes. Save the money those promise to cost you and spend it on a single ferritin test instead. One accurate number beats a cupboard full of guesses.
The practical move, in plain order, looks like this:
- Ask your GP for a serum ferritin and transferrin saturation, taken in the morning.
- If ferritin is at or below 75, raise the iron question using that number, not the word “tired.”
- If you are short on magnesium, vitamin D, B12, or folate, top those up too.
- Layer in the non-drug habits that calm legs at night, set out in the full plan for stopping Restless Legs at night.
How to raise low iron for restless legs without making things worse
The win here is steady legs within a few weeks, and getting there is less about willpower than about doing it the right way. Iron is one of those things where more, faster, can backfire, so a calm approach beats an enthusiastic one.
If your ferritin is low and your GP agrees, the usual first step is an oral iron tablet. Taking it every second day, rather than every day, often lifts your stores just as well and is far gentler on the stomach, which is the reason most people give up.
A little vitamin C, or simply taking it with a glass of orange juice, helps your body absorb it. Keep it away from tea, coffee, and dairy, because all three blunt how much iron gets through.
When tablets are not enough, or your ferritin sits in that 75 to 100 band, intravenous iron is the route the 2024 guideline points to (AASM, 2024). It is a single clinic visit that refills your stores in one go, and for women whose gut never tolerated tablets it is often the thing that finally works. Your GP can refer you.
One firm caution. Iron is not a supplement to megadose on a hunch. Too much iron is genuinely harmful, and some people carry a condition that makes them store iron dangerously well. That is the whole reason the ferritin test comes first: you treat a number you can see, not a feeling. Get tested, then treat, in that order.
What the research actually shows
Two pieces of evidence sit behind the practical advice in this article, and both are worth knowing by name.
The 2024 American Academy of Sleep Medicine clinical practice guideline is the current word on treating Restless Legs Syndrome, and it puts iron front and centre. It recommends regular iron studies for anyone with clinically significant symptoms. It sets the supplementation thresholds described above: ferritin at or below 75 micrograms per litre, or transferrin saturation under 20 per cent (AASM, 2024).
The same guideline reversed two decades of practice by recommending against dopamine-based drugs as the standard first treatment. The reason is that those drugs can make symptoms worse over time, a pattern that affects an estimated 7 to 10 per cent of patients for every year of treatment. That reversal is a big part of why drug-free and iron-first approaches are getting a serious second look.
The strongest published evidence for a non-drug approach comes from a 2016 trial. It compared targeted overnight foot compression against ropinirole, a standard prescription medication for Restless Legs Syndrome.
The compression group recorded a 90 per cent improvement on the Clinical Global Impression scale after eight weeks, against 63 per cent for the drug. That makes the compression roughly 1.4 times more effective, with none of the long-term worsening risk the medication carries (Kuhn et al., 2016).
That trial is the reason Stillr exists. It sits alongside iron as part of a drug-free plan rather than in competition with it.
What Stillr is, and isn’t
Stillr is a drug-free overnight compression sleeve, worn on both legs, built around the targeted-pressure mechanism with the strongest non-drug evidence for Restless Legs Syndrome. It is unisex and sized for adult feet: Regular fits AU women’s 5 to 8, and Large fits AU women’s 8.5 to 11 or men’s 7 to 10.
Stillr is pre-launch in Australia at the founders’ price of AUD $149 for the first 500 pairs. Every pair comes with a 30-Night Sleep Trial, full refund if it does not improve your sleep. You can reserve your pair on the founders’ list at stillr.com.au.
Stillr is not a medication, not a cure, and not a treatment for any disease. It is a wellness product, built around what the research suggests the body responds to. Iron and Stillr are not rivals; sorting your ferritin and calming your legs at night are two parts of the same drug-free plan, and plenty of women will want both.
If “drug-free, on my own terms” is the version of this you have been looking for, join the founders’ list at stillr.com.au and we will tell you the moment your size opens.